In recent years, electrically powered vehicles (hybrid vehicles, electric vehicles, and the like) that obtain driving force through electric power are gaining a large attention. An electrically powered vehicle is generally equipped with a rechargeable battery to store electric power therein for driving a motor. The rechargeable battery degrades with time, and if it continues to be used in a degraded state, it will fail. Accordingly, for the electrically powered vehicle, it is important to grasp how much the rechargeable battery is degraded. In this regard, Japanese Patent Laying-Open No. 2007-074891 (PTL 1) discloses estimating a battery's lifetime from the battery's history of use and warning the user thereof.